Most flash-based systems use something called write-levelling, which is largely a way of randomizing IO (in flash memory, random IO is not a performance problem like it is in hard-drives) so that each block gets eat an equal amount of time.

NAND flash memory has a limited number of write-erase cycles, around 100,000 under current design. Now a write-erase only occurs when the blocks need to be set to zero. IE you can change 0000 to 0001 to 0011 to 0111 to 1111 without going through an erase cycle, (or any combination thereof) however in order to change any bit from 1 to 0 requires that that entire block be erased and re-written. This could prove to be a substantial limitation for the type of storage.

That being said, it’s just as much a limitation for every type of NAND-Flash based storage. If Fusion-IO has come up with a solid write-levelling algorithm and can truly distribute the Io across the entire card, then they by far have the superior product.

As I understand it, most commercially available SSD disks write as a normal disk, which could cause them to run up against that write-erase barrier much sooner. (IE if a disk is 30% full, the first 30% of the drive is most active and will hit the limit far before the end of the address-space.

Assuming of course that the SSD manufacturers haven’t already adjusted to this with a write-levelling algorithm of their own.

This would end that struggle once and for all. probably a 15 second boot time.